Commit 29f08088 authored by Vincenzo Frascino's avatar Vincenzo Frascino Committed by Linus Torvalds
Browse files

kselftest/arm64: check GCR_EL1 after context switch 

This test is specific to MTE and verifies that the GCR_EL1 register is
context switched correctly.

It spawns 1024 processes and each process spawns 5 threads.  Each thread
writes a random setting of GCR_EL1 through the prctl() system call and
reads it back verifying that it is the same.  If the values are not the
same it reports a failure.

Note: The test has been extended to verify that even SYNC and ASYNC mode
setting is preserved correctly over context switching.

Link: https://lkml.kernel.org/r/b51a165426e906e7ec8a68d806ef3f8cd92581a6.1606161801.git.andreyknvl@google.com


Signed-off-by: default avatarVincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Acked-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Tested-by: default avatarVincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Marco Elver <elver@google.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 948e3253

tools/testing/selftests/arm64/mte/Makefile

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# SPDX-License-Identifier: GPL-2.0

# Copyright (C) 2020 ARM Limited



CFLAGS += -std=gnu99 -I.

CFLAGS += -std=gnu99 -I. -lpthread

SRCS := $(filter-out mte_common_util.c,$(wildcard *.c))

PROGS := $(patsubst %.c,%,$(SRCS))

tools/testing/selftests/arm64/mte/check_gcr_el1_cswitch.c

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// SPDX-License-Identifier: GPL-2.0

// Copyright (C) 2020 ARM Limited



#define _GNU_SOURCE



#include <errno.h>

#include <pthread.h>

#include <stdint.h>

#include <stdio.h>

#include <stdlib.h>

#include <time.h>

#include <unistd.h>

#include <sys/auxv.h>

#include <sys/mman.h>

#include <sys/prctl.h>

#include <sys/types.h>

#include <sys/wait.h>



#include "kselftest.h"

#include "mte_common_util.h"



#define PR_SET_TAGGED_ADDR_CTRL 55

#define PR_GET_TAGGED_ADDR_CTRL 56

# define PR_TAGGED_ADDR_ENABLE  (1UL << 0)

# define PR_MTE_TCF_SHIFT	1

# define PR_MTE_TCF_NONE	(0UL << PR_MTE_TCF_SHIFT)

# define PR_MTE_TCF_SYNC	(1UL << PR_MTE_TCF_SHIFT)

# define PR_MTE_TCF_ASYNC	(2UL << PR_MTE_TCF_SHIFT)

# define PR_MTE_TCF_MASK	(3UL << PR_MTE_TCF_SHIFT)

# define PR_MTE_TAG_SHIFT	3

# define PR_MTE_TAG_MASK	(0xffffUL << PR_MTE_TAG_SHIFT)



#include "mte_def.h"



#define NUM_ITERATIONS		1024

#define MAX_THREADS		5

#define THREAD_ITERATIONS	1000



void *execute_thread(void *x)

{

	pid_t pid = *((pid_t *)x);

	pid_t tid = gettid();

	uint64_t prctl_tag_mask;

	uint64_t prctl_set;

	uint64_t prctl_get;

	uint64_t prctl_tcf;



	srand(time(NULL) ^ (pid << 16) ^ (tid << 16));



	prctl_tag_mask = rand() & 0xffff;



	if (prctl_tag_mask % 2)

		prctl_tcf = PR_MTE_TCF_SYNC;

	else

		prctl_tcf = PR_MTE_TCF_ASYNC;



	prctl_set = PR_TAGGED_ADDR_ENABLE | prctl_tcf | (prctl_tag_mask << PR_MTE_TAG_SHIFT);



	for (int j = 0; j < THREAD_ITERATIONS; j++) {

		if (prctl(PR_SET_TAGGED_ADDR_CTRL, prctl_set, 0, 0, 0)) {

			perror("prctl() failed");

			goto fail;

		}



		prctl_get = prctl(PR_GET_TAGGED_ADDR_CTRL, 0, 0, 0, 0);



		if (prctl_set != prctl_get) {

			ksft_print_msg("Error: prctl_set: 0x%lx != prctl_get: 0x%lx\n",

						prctl_set, prctl_get);

			goto fail;

		}

	}



	return (void *)KSFT_PASS;



fail:

	return (void *)KSFT_FAIL;

}



int execute_test(pid_t pid)

{

	pthread_t thread_id[MAX_THREADS];

	int thread_data[MAX_THREADS];



	for (int i = 0; i < MAX_THREADS; i++)

		pthread_create(&thread_id[i], NULL,

			       execute_thread, (void *)&pid);



	for (int i = 0; i < MAX_THREADS; i++)

		pthread_join(thread_id[i], (void *)&thread_data[i]);



	for (int i = 0; i < MAX_THREADS; i++)

		if (thread_data[i] == KSFT_FAIL)

			return KSFT_FAIL;



	return KSFT_PASS;

}



int mte_gcr_fork_test(void)

{

	pid_t pid;

	int results[NUM_ITERATIONS];

	pid_t cpid;

	int res;



	for (int i = 0; i < NUM_ITERATIONS; i++) {

		pid = fork();



		if (pid < 0)

			return KSFT_FAIL;



		if (pid == 0) {

			cpid = getpid();



			res = execute_test(cpid);



			exit(res);

		}

	}



	for (int i = 0; i < NUM_ITERATIONS; i++) {

		wait(&res);



		if (WIFEXITED(res))

			results[i] = WEXITSTATUS(res);

		else

			--i;

	}



	for (int i = 0; i < NUM_ITERATIONS; i++)

		if (results[i] == KSFT_FAIL)

			return KSFT_FAIL;



	return KSFT_PASS;

}



int main(int argc, char *argv[])

{

	int err;



	err = mte_default_setup();

	if (err)

		return err;



	ksft_set_plan(1);



	evaluate_test(mte_gcr_fork_test(),

		"Verify that GCR_EL1 is set correctly on context switch\n");



	mte_restore_setup();

	ksft_print_cnts();



	return ksft_get_fail_cnt() == 0 ? KSFT_PASS : KSFT_FAIL;

}